This project is aimed primarily at the study of the metabolism and ultrastructure of the nervous system and its innervated structures. Electron microscope autoradiography is a major tool which is at present used primarily to determine the intracellular sites of 1) the synthesis, storage and disposition of neurotransmitters; and 2) the distribution and synthesis of macromolecules such as acetylcholinesterase, acetylcholine receptor, etc. which are under neurotrophic control.